Article

A retrospective analysis of glycol and toxic alcohol ingestion: Utility of anion and osmolal gaps

Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City, IA, 52242, USA. .
BMC Clinical Pathology 01/2012; 12(1):1. DOI: 10.1186/1472-6890-12-1
Source: PubMed

ABSTRACT

Patients ingesting ethylene glycol, isopropanol, methanol, and propylene glycol ('toxic alcohols') often present with non-specific signs and symptoms. Definitive diagnosis of toxic alcohols has traditionally been by gas chromatography (GC), a technique not commonly performed on-site in hospital clinical laboratories. The objectives of this retrospective study were: 1) to assess the diagnostic accuracy of the osmolal gap in screening for toxic alcohol ingestion and 2) to determine the common reasons other than toxic alcohol ingestion for elevated osmolal gaps.
Electronic medical records from an academic tertiary care medical center were searched to identify all patients in the time period from January 1, 1996 to September 1, 2010 who had serum/plasma ethanol, glucose, sodium, blood urea nitrogen, and osmolality measured simultaneously, and also all patients who had GC analysis for toxic alcohols. Detailed chart review was performed on all patients with osmolal gap of 9 or greater.
In the study period, 20,669 patients had determination of serum/plasma ethanol and osmolal gap upon presentation to the hospitals. There were 341 patients with an osmolal gap greater than 14 (including correction for estimated contribution of ethanol) on initial presentation to the medical center. Seventy-seven patients tested positive by GC for one or more toxic alcohols; all had elevated anion gap or osmolal gap or both. Other than toxic alcohols, the most common causes for an elevated osmolal gap were recent heavy ethanol consumption with suspected alcoholic ketoacidosis, renal failure, shock, and recent administration of mannitol. Only 9 patients with osmolal gap greater than 50 and no patients with osmolal gap greater than 100 were found to be negative for toxic alcohols.
Our study concurs with other investigations that show that osmolal gap can be a useful diagnostic test in conjunction with clinical history and physical examination.

  • Source
    • "This effect leads to a changing pattern of increased osmolal gap followed by an increased anion gap over time. This is commonly noted in the ED [2], although the osmolal gap is not suggested to be used as screening for toxic alcohol poisoning [3]. Instead, rapid and specific identification of the causes of the increased osmolal and/or anion gaps by VA or EG testing helps guide clinical treatment strategies [4]. "

    Full-text · Article · Oct 2015
  • Source
    • "This effect leads to a changing pattern of increased osmolal gap followed by an increased anion gap over time. This is commonly noted in the ED [2], although the osmolal gap is not suggested to be used as screening for toxic alcohol poisoning [3]. Instead, rapid and specific identification of the causes of the increased osmolal and/or anion gaps by VA or EG testing helps guide clinical treatment strategies [4]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Objectives: Clinical analysis of volatile alcohols (i.e. methanol, ethanol, isopropanol, and metabolite acetone) and ethylene glycol (EG) generally employs separate gas chromatography (GC) methods for analysis. Here, a method for combined analysis of volatile alcohols and EG is described. Design and methods: Volatile alcohols and EG were extracted with 2:1 (v:v) acetonitrile containing internal standards (IS) 1,2 butanediol (for EG) and n-propanol (for alcohols). Samples were analyzed on an Agilent 6890 GC FID. The method was evaluated for precision, accuracy, reproducibility, linearity, selectivity and limit of quantitation (LOQ), followed by correlation to existing GC methods using patient samples, Bio-Rad QC, and in-house prepared QC material. Results: Inter-day precision was from 6.5-11.3% CV, and linearity was verified from down to 0.6mmol/L up to 150mmol/L for each analyte. The method showed good recovery (~100%) and the LOQ was calculated to be between 0.25 and 0.44mmol/L. Patient correlation against current GC methods showed good agreement (slopes from 1.03-1.12, and y-intercepts from 0 to 0.85mmol/L; R(2)>0.98; N=35). Carryover was negligible for volatile alcohols in the measuring range, and of the potential interferences tested, only toluene and 1,3 propanediol interfered. The method was able to resolve 2,3 butanediol, diethylene glycol, and propylene glycol in addition to the peaks quantified. Conclusions: Here we describe a simple procedure for simultaneous analysis of EG and volatile alcohols that comes at low cost and with a simple liquid-liquid extraction requiring no derivitization to obtain adequate sensitivity for clinical specimens.
    Full-text · Article · Sep 2015 · Clinical biochemistry
  • Source
    • "Dilution protocols were modified following identification of this problem.[17] A protocol for evaluation of possible toxic alcohol or glycol exposure was developed based on osmolal gap.[1819] "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: Autoverification is a process of using computer-based rules to verify clinical laboratory test results without manual intervention. To date, there is little published data on the use of autoverification over the course of years in a clinical laboratory. We describe the evolution and application of autoverification in an academic medical center clinical chemistry core laboratory. Subjects and Methods: At the institution of the study, autoverification developed from rudimentary rules in the laboratory information system (LIS) to extensive and sophisticated rules mostly in middleware software. Rules incorporated decisions based on instrument error flags, interference indices, analytical measurement ranges (AMRs), delta checks, dilution protocols, results suggestive of compromised or contaminated specimens, and ‘absurd’ (physiologically improbable) values. Results: The autoverification rate for tests performed in the core clinical chemistry laboratory has increased over the course of 13 years from 40% to the current overall rate of 99.5%. A high percentage of critical values now autoverify. The highest rates of autoverification occurred with the most frequently ordered tests such as the basic metabolic panel (sodium, potassium, chloride, carbon dioxide, creatinine, blood urea nitrogen, calcium, glucose; 99.6%), albumin (99.8%), and alanine aminotransferase (99.7%). The lowest rates of autoverification occurred with some therapeutic drug levels (gentamicin, lithium, and methotrexate) and with serum free light chains (kappa/lambda), mostly due to need for offline dilution and manual filing of results. Rules also caught very rare occurrences such as plasma albumin exceeding total protein (usually indicative of an error such as short sample or bubble that evaded detection) and marked discrepancy between total bilirubin and the spectrophotometric icteric index (usually due to interference of the bilirubin assay by immunoglobulin (Ig) M monoclonal gammopathy). Conclusions: Our results suggest that a high rate of autoverification is possible with modern clinical chemistry analyzers. The ability to autoverify a high percentage of results increases productivity and allows clinical laboratory staff to focus attention on the small number of specimens and results that require manual review and investigation.
    Full-text · Article · Mar 2014
Show more